Chapter 4, Problem 4.37E

Interpretation Introduction

(a)

Interpretation:

The formula weight in atomic mass units for the given binary ionic compound is to be determined.

Concept introduction:

Ionic compounds are those compounds that have the strong electrostatic force of attraction between the oppositely charged ions. A huge amount of heat is required to separate these oppositely charged ions. Therefore, the melting point of ionic solids is high.

Answer to Problem 4.37E

The formula weight in atomic mass units for the given binary ionic compound is $\text{61}\text{.98}\text{u}$.

Explanation of Solution

The formula weight of binary compounds is the sum of atomic weight of each atom.

The formula weight of ${\text{Na}}_{\text{2}}\text{O}$ is calculated by the formula,

$\text{Formula}\text{weight}=\left(2\times \text{atomic}\text{weight}\text{of}\text{Na}\right)+\left(1\times \text{atomic}\text{weight}\text{of}\text{O}\right)$ …(1)

The atomic weights of $\text{Na}$ and $\text{O}$ are $\text{22}\text{.99}\text{u}$ and $16.0\text{u}$, respectively.

Substitute the atomic weight of $\text{Na}$ and $\text{O}$ in equation (1).

$\begin{array}{rll}\text{Formula}\text{weight}& =& \left(2\times \text{22}\text{.99}\text{u}\right)+\left(1\times 16.0\text{u}\right)\\ & =& \left(45.98+16.0\right)\text{u}\\ & =& \text{61}\text{.98}\text{u}\end{array}$

Conclusion

The formula weight in atomic mass units for the given binary ionic compound is $\text{61}\text{.98}\text{u}$.

Interpretation Introduction

(b)

Interpretation:

The formula weight in atomic mass units for the given binary ionic compound is to be determined.

Concept introduction:

Ionic compounds are those compounds that have the strong electrostatic force of attraction between the oppositely charged ions. A huge amount of heat is required to separate these oppositely charged ions. Therefore, the melting point of ionic solids is high.

Answer to Problem 4.37E

The formula weight in atomic mass units for the given binary ionic compound is $71.85\text{u}$.

Explanation of Solution

The formula weight of binary compounds is the sum of atomic weight of each atom.

The formula weight of $\text{FeO}$ is calculated by the formula,

$\text{Formula}\text{weight}=\left(1\times \text{atomic}\text{weight}\text{of}\text{Fe}\right)+\left(1\times \text{atomic}\text{weight}\text{of}\text{O}\right)$ …(2)

The atomic weights of $\text{Fe}$ and $\text{O}$ are $\text{55}\text{.85}\text{u}$ and $16.00\text{u}$, respectively.

Substitute the atomic weight of $\text{Fe}$ and $\text{O}$ in equation (2).

$\begin{array}{rll}\text{Formula}\text{weight}& =& \left(1\times 55.85\text{u}\right)+\left(1\times \text{16}\text{.00}\text{u}\right)\\ & =& 71.85\text{u}\end{array}$

Conclusion

The formula weight in atomic mass units for the given binary ionic compound is $71.85\text{u}$.

Interpretation Introduction

(c)

Interpretation:

The formula weight in atomic mass units for the given binary ionic compound is to be determined.

Concept introduction:

Ionic compounds are those compounds that have the strong electrostatic force of attraction between the oppositely charged ions. A huge amount of heat is required to separate these oppositely charged ions. Therefore, the melting point of ionic solids is high.

Answer to Problem 4.37E

The formula weight in atomic mass units for the given binary ionic compound is $\text{271}\text{.32}\text{u}$.

Explanation of Solution

The formula weight of binary compounds is the sum of atomic weight of each atom.

The formula weight of ${\text{PbS}}_2$ is calculated by the formula,

$\text{Formula}\text{weight}=\left(1\times \text{atomic}\text{weight}\text{of}\text{Pb}\right)+\left(2\times \text{atomic}\text{weight}\text{of}\text{S}\right)$ …(3)

The atomic weights of $\text{Pb}$ and $\text{S}$ are $\text{207}\text{.2}\text{u}$ and $32.06\text{u}$, respectively.

Substitute the atomic weight of $\text{Pb}$ and $\text{S}$ in equation (3).

$\begin{array}{rll}\text{Formula}\text{weight}& =& \left(1\times 207.2\text{u}\right)+\left(2\times \text{32}\text{.06}\text{u}\right)\\ & =& 207.2\text{u}+64.12\text{u}\\ & =& \text{271}\text{.32}\text{u}\end{array}$

Conclusion

The formula weight in atomic mass units for the given binary ionic compound is $\text{271}\text{.32}\text{u}$.

Interpretation Introduction

(d)

Interpretation:

The formula weight in atomic mass units for the given binary ionic compound is to be determined.

Concept introduction:

Ionic compounds are those compounds that have the strong electrostatic force of attraction between the oppositely charged ions. A huge amount of heat is required to separate these oppositely charged ions. Therefore, the melting point of ionic solids is high.

Answer to Problem 4.37E

The formula weight in atomic mass units for the given binary ionic compound is $\text{133}\text{.28}\text{u}$.

Explanation of Solution

The formula weight of binary compounds is the sum of atomic weight of each atom.

The formula weight of ${\text{AlCl}}_3$ is calculated by the formula,

$\text{Formula}\text{weight}=\left(\text{1}\times \text{atomic}\text{weight}\text{of}\text{Al}\right)+\left(3\times \text{atomic}\text{weight}\text{of}\text{Cl}\right)$ …(4)

The atomic weights of $\text{Al}$ and $\text{Cl}$ are $\text{26}\text{.93}\text{u}$ and $35.45\text{u}$, respectively.

Substitute the atomic weight of $\text{Al}$ and $\text{Cl}$ in equation (4).

$\begin{array}{rll}\text{Formula}\text{weight}& =& \left(1\times \text{26}\text{.93}\text{u}\right)+\left(3\times 35.45\text{u}\right)\\ & =& \text{26}\text{.93}\text{u}+106.35\text{u}\\ & =& \text{133}\text{.28}\text{u}\end{array}$

Conclusion

The formula weight in atomic mass units for the given binary ionic compound is $\text{133}\text{.28}\text{u}$.